The invention disclosed herein relates to disposable absorbent articles, particularly sanitary napkins, and more particularly to sanitary napkins with laterally extending flaps having longitudinal stretch which provides curvature to the sanitary napkin for improved bodily fit while, at the same time providing protection against soiling and improved adherence to a wearer""s panty.
Catamenial pads, such as sanitary napkins, and related disposable absorbent articles which provide for the collection of menses and other bodily discharges are well known in the art. It has long been an object of the art to provide sanitary napkins which readily intercept menses upon discharge from the wearer.
Unitary disposable absorbent articles such as catamenial pads or incontinent pads all have the same basic structure. An absorbent core is encased between a liquid pervious topsheet and a liquid impervious backsheet. Numerous variations of and elements in addition to the basic topsheet, backsheet, and absorbent core arrangements are known. Each additional element is usually directed to improving a specific characteristic of the catamenial pad or incontinent pad.
Disposable absorbent articles have been provided with elastic members to improve the side leakage performance of such products. U.S. Pat. No. 3,860,003, issued to Buell on Jan. 14, 1975, discloses elasticized disposable absorbent articles wherein an elastic member is positioned in the side flap of the product between the topsheet and the backsheet. The elasticized portion of each side flap is positioned sufficiently remote from the semi-rigid absorbent body to permit an elasticized contractible line through the side flap. The side flap is gathered by the elastic member such that a boat-like configuration for the pad is presented and the side flaps form a barrier along the edges of the product. In particular, FIG. 5 and FIG. 6 of the Buell patent show incontinent pads having various shaped absorbent cores wherein an elastic member is positioned along the side edges of the product.
European Patent Application 0 091 412 A2, published on Oct. 12, 1983, in the name of Widlund, adopts the configuration shown in the Buell ""003 patent and specifically relates it to a feminine hygiene product. The Widlund application teaches a sanitary napkin with elastic means spaced from the core to thereby raise and form barriers against lateral leakage from the product. FIG. 1 of the Widlund patent shows the boat-like shape of the product with the side flaps forming lateral barriers to the flow of exudates.
U.S. Pat. No. 4,597,761 issued to Buell on Jul. 1, 1986, discloses an elasticized insert product for use as an incontinent pad or sanitary napkin having elastic in the side flaps. One or more elastic strands are positioned in the side flap to allow the product to assume the boat-like configuration shown in FIG. 1 with the side flaps extending upwardly to form barrier walls against lateral leakage.
U.S. Pat. No. 4,579,556 issued to McFarland on Apr. 1, 1986, further defines the Buell ""003 concept for incontinent pads by creating a dual baffle structure at the edges. The impervious backing sheet is folded over the topsheet and the absorbent layer and fastened to the topsheet so that when the elastic contracts, the pad bows with the elasticized fold raising above the surface of the pad to form a baffle. A lower baffle is formed over the absorbent with the upstanding baffle containing the elastic.
U.S. Pat. No. 4,668,230 issued to D""Amico et al. on May 26, 1987, adopts the Buell ""003 approach and the Widlund application approach by extending the elastics to the ends of the pad and allowing the pad to assume a cup-like or boat-like shape. In particular, the elastics are secured at one end of the pad and extend at least two-thirds of the length of the remainder of the pad to give the proper trough-like shape to the pad. However, side flaps that stand up are not created in the D""Amico et al. patent.
UK Patent Application 2 168 253A, Baird and Robert published on Jun. 18, 1986, discloses an incontinent pad or sanitary napkin provided with liquid impermeable upwardly folded side flaps. The side flaps are formed by extending the backsheet beyond the absorbent core along at least part of the lateral edges of the absorbent core. A seal is formed adjacent the side edge of the absorbent core to present a dual baffle against leakage in the sides of the pad.
U.S. Pat. No. 4,701,177 issued to Ellis et al. on Oct. 20, 1987, provides a pad that is generally thicker in the center portion than at the ends of the pad. The upstanding side portions in the middle of each longitudinal edge are in the area where the absorbent core is hourglass or narrower shaped. The pad is also curved into a boat-like shape to generally conform to the pudendum of the wearer. The elastic film members are secured in the side flap of the sanitary napkin or incontinent pad between the topsheet and the backsheet to form the upstanding baffles.
U.S. Pat. No. 5,032,121 issued to Mokry on Jul. 16, 1991 adopts the Buell ""003 and Widlund approach by placing the elasticized baffles in an hourglass-shaped pad with an hourglass-shaped absorbent core. The sanitary napkin includes a pair of elastic members affixed between the cover and the backsheet outward of the seal line and aligned adjacent to the central portion of the core. The elastic members cause the pad to acquire a cup-shaped configuration which corresponds to the perineal area of the user.
U.S. Pat. No. 5,234,422 issued to Sneller, et al. on Aug. 10, 1993 improves on earlier articles by wrapping the edges of the topsheet and the backsheet with an elasticized member. This elasticized member is preferably a laminate of an elastomeric layer and a coverstock layer. Since the coverstock layer is on the outside of the product, the sanitary napkin is provided with soft longitudinal edges which contact the wearer during use.
Each of these patents is related to providing elasticization in a sanitary napkin or incontinent pad. In each of these concepts, the elastic members are positioned in the side flap between the topsheet and the backsheet to allow the side flap to be gathered and to form upstanding baffles along the side edges of the product to slow or stop the lateral flow of body exudates beyond the edge of the pad. However, since the baffles slow or stop the lateral leakage by forming a seal between the baffle and the wearer""s body, there is still a risk of leakage and resultant soiling of a wearer""s undergarments due to seal failure.
Another approach to providing sanitary napkins with improved means for protection of a wearer""s undergarment is found in U.S. Pat. No. B1 4,589,876 Reexamination Certificate issued Apr. 27, 1993 to Van Tilburg. This patent describes a sanitary napkin with flaps that extend laterally from a longitudinal edge of a central absorbent core. The flaps wrap around the crotch portion of the undergarment preventing soiling thereof.
One of the embodiments of U.S. Pat. No. 4,911,701 issued to Mavinkurve on Mar. 27, 1990 describes a catamenial with longitudinally disposed elastic strips in a pair of laterally extending flaps. The elastic strips cause the flaps to assume a concave configuration on their garment facing side. This concave configuration is said to provide greater resistance to buckling when the panty is raised by a wearer. The invention is also said to provide a convex shape to the body facing portion of the sanitary napkin and allow adhesive free placement of the flaps.
U.S. Pat. No. 4,940,462 issued to Solerno on Jul. 10, 1990 discloses a sanitary napkin having expandable flaps. The expandable flaps are made of a stretchable material. This stretchability is said to allow the flaps to extend along the full length of the sanitary napkin without bunching. While the Solerno patent mentions the use of attachment adhesives, the type and location of such adhesives is unclear.
While the laterally extending flaps described in the above patents provide protection against soiling by covering the sides of a wearer""s panties, they are not designed to conform to a wearer""s anatomy in the pudendal region. Further, although the articles described in the Mavinkurve and Solerno patents are said to have longitudinally directed extensibility, this extensibility fails to provide a shape to the article offering such improved conformity.
It is particularly desirable to improve the wearing comfort of catamenial pads while preventing increased soiling of the garments surrounding the pad. Therefore, it is an object of the present invention to provide a disposable absorbent article providing improved protection against soiling while providing improved wearer comfort. It is a further object of the present invention to provide an elasticized catamenial pad or incontinence pad that protects against lateral soiling while improving the wearer""s comfort by better conforming to the shape of the pudendal region. Also, it is an object of this invention to provide a sanitary napkin having an arcuate shape that more readily conforms to a wearer""s body. Finally, it is an object of this invention to provide a sanitary napkin having elasticized flaps with longitudinal extensibility which not only provide an arcuate shape to the sanitary napkin but also provide improved adherence to a wearer""s panty.
According to the present invention a unitary disposable absorbent article, such as a catamenial pad or an incontinent pad, is provided with laterally extending flaps having longitudinally oriented elastic extensibility. The flaps are joined to and extend laterally outboard of the longitudinal edges of a central absorbent body. In a preferred sanitary napkin embodiment of the present invention the central absorbent body comprises a fluid permeable topsheet, a fluid impermeable backsheet, an absorbent core disposed between the topsheet and the backsheet, and an acquisition component disposed between the absorbent core and the topsheet and the laterally extending, elastically extensible flaps comprise a separate, mechanically prestrained laminate of a flap cushion material, a flap barrier material and a flap elastic. The central absorbent body and the flaps of the preferred embodiment of the present invention are also provided with means for attaching the sanitary napkin to a wearer""s panty. The flaps are joined to the central absorbent body in a longitudinally stretched condition such that, when the flaps return to their unstretched condition, the sanitary napkin is provided with an arcuate shape which more readily conforms to the shape of a wearer""s pudendal region. The longitudinally oriented elastic extensibility of the flaps also results in improved reliability of the panty attachment means because the flaps can extend and contract along with the panty in response to normal wearer movements.